Humidification system for aircraft

ABSTRACT

An aircraft humidification system includes a first duct configured to guide a first air stream, and a second duct configured to guide a second air stream, the second duct including a humidifier for humidifying the air stream in the second duct. A first conduit directs part of the second air stream to the first duct. The first conduit includes a first conduit inlet leading into the first duct and a first conduit outlet extending from the second duct. A second conduit directs part of the first air stream to the second duct, the second conduit including a second conduit inlet leading into the second duct and a second conduit outlet extending from the first duct. The first conduit outlet is arranged downstream of the humidifier, the second conduit inlet is arranged downstream of the first conduit outlet and the first conduit inlet is arranged downstream of the second conduit outlet.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority to, under relevantsections of 35 U.S.C. § 119, European Patent Application No. 21202033.3,filed Oct. 11, 2021, the entire contents of which are herebyincorporated by reference.

TECHNICAL FIELD

The invention relates to the field of aircraft humidifier systems and inparticular to aircraft humidifier systems that can be installed incramped spaces and in existing environmental control systems (ECS) ofaircrafts.

BACKGROUND

There is a need to provide humidifiers to existing aircrafts. A lot ofcommercial aircrafts that are currently in use are built withouthumidification systems for the AC air that is transported and providedto the cabin, crew space, cockpit and so on. The interest to installhumidification systems in existing aircraft is, however, rather big andthis interest poses certain technical challenges to such humidificationsystems. These technical challenges include limited space and highrequirements regarding pressure issues, in particular pressure loss andpressure increase situations, in the ventilation systems of aircrafts.

In aircrafts, the cabin air is typically supplied with some sort ofsupply air. The supply air can be a mixture of recycled cabin air andfresh outside air, while alternatively the supply air consists of onlyfresh outside air. The supply air is normally conditioned anddistributed via stems or ducts to cabin zones, the cockpit and/or crewresting areas. One can imagine that a possible solution to install ahumidifier in an existing ventilation system in an aircraft could be toinstall a humidifier with high capacity, which would be comparably bigin size, in the ventilation system, whereby this humidifier ispositioned prior to any division of air streams, such as air streams todifferent cabin zones, cockpit and crew rest areas. An alternative tothat solution would be to use a separate humidifier of smaller size ineach partial air stream that goes to the consumers and thus the cabin,the cockpit or crew rest areas. As mentioned, in many cases there is,however, no space for one big humidifier nor several small humidifiers.Additionally, if many smaller humidifiers for each of the air streamsare used, maintenance and economic concerns arise since many smallhumidifiers lead to challenges regarding faults over time and highercosts.

One potential solution could be to lead the air stream, prior to anydistribution via partial air streams and ducts, through a comparablysmall humidifier. This solution would, however, result in too high apressure drop and certainly lead to a humidification system and aventilation system that is operating outside the technically acceptableboundaries, which can lead to problems in the ventilation system.

BRIEF SUMMARY OF THE DISCLOSURE

In view of the above it is an object of the present invention to providea humidification system for aircrafts that is economic, energy savingand compact.

Another object is to provide a humidification system that can beinstalled in existing aircrafts and that can operate within the giventechnical boundaries of ventilation systems and/or environmental controlsystems (ECS) of aircrafts.

The inventors of the present invention have discovered that it ispossible to take the given parameters such as space, pressure loss orincrease and low energy use into account and provide a humidificationsystem for aircrafts that can be installed in tight spaces in existingECS of aircrafts. The basic concept the inventor discovered is to useone single humidifier in a partial air stream that goes to the consumerand over humidifies this partial air stream and then re-distributes thisover humidified partial air stream into chosen air streams that flowtowards the consumer and at the same time normalize the humidity in thepartial air stream by re-distributing air from other air streams that goto consumers and in which the other air streams comprise dry and warmair. The re-distribution is done prior to any air reaching the consumer.Such a humidification system solves the above-mentioned problems andshortcomings.

Disclosed herein is a humidification system for aircrafts, comprising:

a first duct configured to guide a first air stream;

a second duct configured to guide a second air stream, said second ductcomprising a humidifier for humidifying the air in the second duct;

a first conduit for directing a part of the second air stream to thefirst duct thus interconnecting the second duct with the first duct,said first conduit comprising a first conduit inlet leading into thefirst duct and a first conduit outlet from the second duct; and

a second conduit for directing a part of the first air stream to thesecond duct thus interconnecting the first duct with the second duct,said second conduit comprising a second conduit inlet leading into thesecond duct and a second conduit outlet from the first duct, wherein thefirst conduit outlet is arranged downstream of the humidifier, thesecond conduit inlet is arranged downstream of the first conduit outletand wherein the first conduit inlet is arranged downstream the secondconduit outlet.

Prior to reaching the humidifier the second duct may comprise a supplyair stream and similarly prior to reaching the second conduit outlet,the first duct may comprise a supply air stream.

The humidification system according to the above embodiment can beinstalled in existing ECS (and new ECS) of aircrafts within thepre-described pressure loss or pressure increase boundaries withoutrequiring substantial additional energy and within the available spacein the aircraft body.

The humidification system according to the above embodiment can furtherbe scaled and also works for three ducts, four ducts and so on wherebyeach of the ducts is designed to be guided towards a consumer space suchas for example the cockpit, cabin, galley and/or crew resting areas.

In a further embodiment, the humidification system comprises an airsupply duct configured to guide a dry supply air stream and a firsttwo-way manifold connected to the air supply duct, the first duct andthe second duct, whereby the air is configured to flow from the airsupply duct into the two-way manifold and then partially into the firstduct and the second duct forming the first air stream and the second airstream.

In an embodiment, the humidifier of the humidification system is anadiabatic humidifier or preferably an adiabatic evaporation humidifier,or even more preferably an adiabatic contact humidifier.

The adiabatic humidifier may comprise a contact humidifier pad that iskept wet via a water supply in order to humidify the second air stream.

An adiabatic humidifier does not require energy for providing humidityto the second air stream.

In an embodiment, a two-way manifold may be configured to split theheated supply air stream at least more or less equally into the firstair stream and the second air stream. Additionally, the first conduitand the second conduit may be configured to split the second air streamand the first air stream at least more or less equally.

The foregoing split may help to provide equal air quality to the entirecabin including the cockpit and crew rest areas and lavatories.

In a further embodiment, the humidification system may comprise a bypassor bypass duct configured to bypass the humidifier on the second duct.

Such a bypass may be used in order to ensure that there are nosubstantial pressure losses or pressure increases present. In addition,the bypass may comprise a restrictor that is fixedly installed tobalance the air flow in the bypass. In an alternative embodiment, thebypass may contain an electronically and potentially remotely controlledcontrolling element for adjusting the bypassing air according to ameasured pressure.

The controlling element(s) disclosed herein may be a fan, a valve or arestrictor, wherein the restrictor could thereby be a fixed oradjustable restrictor.

Any of the first and second ducts or both or any of the first and secondconduits may comprise restrictors to balance air flows. The restrictorsmay be fixedly installed restrictors or adjustable restrictors.

The restrictor(s) may be designed as plate-shaped, preferably circularlyshaped plate-like elements with holes through which the air stream canpass. Such restrictors may be installed in any of the conduits or theducts. If the restrictors are adjustable, the restrictors may bepivotally installed in the ducts or conduits so that they can bepositioned from parallel to the air stream and up to 90 degrees to theair stream. Servomotors may be used to control the position ofadjustable restrictors.

Any of the first and second duct or both or any of the first and secondconduits may additionally comprise a pressure sensor that is connectedto a controller, which controller then steers and regulates the valvesin the humidification system, and in particular, the valve of thebypass.

In an embodiment, the first conduit and the second conduit may bearranged in one duct, whereby the one duct has a dividing wall toaccommodate both conduits; namely, the first conduit and the secondconduit.

This latter arrangement may increase space efficiency, ease installationand handling of the humidification system.

In another embodiment, the humidifier may comprising a humidifying padfor humidifying the second air stream. The humidifying pad may be keptwet via a water supply pipe or the like.

The advantage of a humidifying pad is that no energy needs to besupplied to the humidifier and that bacteria and dirt is kept on the padand therefore does not enter the ECS of the aircraft.

In an embodiment, the first air stream and the second air stream maycomprise humidified air downstream the first conduit inlet anddownstream the second conduit inlet, respectively.

Thus, the first duct and the second duct supply warm and humidified airinto the cabin, cockpit or crew rest areas.

Further, the first duct and/or the second duct may comprise a heatingelement in order to adjust the temperature of the air supplied to theconsumers prior to delivery. In the second duct, the heating element maybe arranged upstream the humidifier.

According to at least one embodiment of the humidification system, thefirst conduit and/or the second conduit comprises a controlling element.

In an embodiment, the first duct and/or the second duct comprises acontrolling element, for example, in the form of valves or fans. Thevalves may be centrally controlled and adjusted, depending on pressuresensors arranged in the first and second duct, respectively.

The first and/or the second duct may comprise pressure sensors in orderto survey the pressure. The pressure sensors may be connected to acontrol unit or the like, which control unit is capable of steering theECS.

In a further embodiment, the first duct and the second duct may comprisemixing elements downstream of the first conduit inlet and the secondconduit inlet, respectively.

These mixing elements may ensure a good mixing of the humidified andnon-humidified air downstream of the first conduit inlet on the firstduct and downstream from the second conduit inlet on the second duct.

The terms “upstream” and “downstream” used herein refer always to thepresent air flow direction in the duct or conduit considered. Downstreamthereby means flowing along the air stream, and upstream thereby meansagainst the flow or flowing of the air stream.

The embodiments illustrated herein can be combined and various featuresof one embodiment can be introduced in other embodiments. The featuresillustrated in one embodiment may be applied in another embodiment. Noneof the features are in particular excluded from being employed orimplemented in another embodiment shown herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, for exemplary purposes, inmore detail by way of an embodiment(s) and with reference to theenclosed drawings, in which:

FIG. 1 schematically illustrates a diagrammatic view of an embodiment ofthe invention; and

FIG. 2 schematically illustrates a cross-sectional view of an embodimentof the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates the general and basic concept of the humidificationsystem 1 according to the invention. The humidification system 1comprises an air supply duct 2, a two-way manifold 4, a first duct 6 anda second duct 10. The two-way manifold 4 is connected to the air supplyduct 2, the first duct 6 and the second duct 10. A supply air streamcomprising fresh outside air and recycled cabin air, which supply airstream is warm and dry, is divided in the two-way manifold 4 into afirst air stream in the first duct 6 and a second air stream in thesecond duct 10. The first air stream and the second air stream maycomprise similar or the same amount of air and thus the same air flowrate. This air flow rate(s) may, however, be adapted and changeddepending on circumstances and on how many ducts and therewith how manyspaces within the aircraft need to be served with humidified or treatedair. The second duct 10 comprises a humidifier 28, which may be of theadiabatic type, said humidifier 28 having an inlet 42 and an outlet 44.The second air stream is over humidified in the humidifier 28 to a highlevel so that it can be re-distributed via a first conduit 8 having afirst conduit inlet 22 connected to the second duct 10, the firstconduit inlet 22 being located downstream of the humidifier 22 on thesecond duct 10, to a first conduit outlet 20 connected to the first duct6. In order to balance the air humidity in the second duct 10 a secondconduit 12 is provided, the second conduit 12 comprising a secondconduit outlet 36 connected to the first duct 6 and a second conduitinlet 34 connected to the second duct 10 downstream of the first conduitoutlet 22. The second conduit outlet 36 is located upstream the firstconduit inlet 20. The second and first conduits 12, 8 are therewithcapable to re-distribute dry warm air from the first duct 6 and coldover humidified air from the second duct 10 so that the air streams thatare delivered to the consumers 48 are of equal quality, thus humidityand temperature.

The second duct 10 may comprise a bypass 30, which bypass 30 allows acertain amount of the second air stream to bypass the humidifier 28.This bypass 30 is, in normal operation, closed but it can be opened incase there is a pressure loss somewhere in the second duct 10. Asmentioned previously the bypass 30 may comprise a fixedly installedrestrictor, in which the restrictor is adapted to balance theventilation system. Such restrictors may be called passive restrictorsherein.

Any of the ducts and/or conduits may comprise such passive restrictors.

Since the humidification system 1 is taking into account the operatingparameters of the environmental control system (ECS) of the aircraftincluding, but not limited to pressure requirements in the entireventilation system, the correct operation of the ECS is maintained. Inorder to further provide controlling instruments and surveillance tools,pressure sensors 18 and controlling elements 16 in the form of valves,fans or restrictors (fixed or adjustable), are provided at variouspositions in the humidification system 1. The pressure sensors 18 areoptional and can be put where needed in order to survey the correctoperation of the humidification system and the ECS. In case the pressuresensors 18 detected a pressure loss in the system, the accordingcontrolling element 16 may be engaged and a valve may be further opened,or a fan speed may be increased. If a pressure increase is detected byany of the pressure sensors 18, the respective controlling element 16may be restricted, thus a valve opening may be reduced, or a fan speeddecreased.

The pressure sensors 18 may be positioned strategically in thehumidification system 1, such as for example in the bypass 30, in thefirst duct 6 upstream the consumers 48, or in the second duct 10upstream the consumers 48. Each pressure sensor 18 may be arrangedtogether and therewith close to a controlling element 16. Controllingelements 16 may thus be arranged upstream from the consumers 48 in thefirst and/or second ducts 6, 10. Likewise, controlling elements 16 andpressure sensors 18 may be arranged in the first conduit 8 and/or thesecond conduit 12.

Again, the controlling elements 16 and the pressure sensors 18 areoptional solutions of the invention and the humidification system 1 isdesigned to work without these elements. In addition, the bypass 30 isalso an optional solution and is, for instance, not shown in FIG. 2 .

The arrows in FIG. 1 illustrate the general flow direction of the airstreams in FIG. 1 .

FIG. 2 shows another embodiment of the invention in a schematiccross-sectional view. The humidification system 1′ of FIG. 2 isillustrated in a similar manner as FIG. 1 , but without controllingelements and/or pressure sensors. The bypass 30′ in FIG. 2 is arrangedwithin the humidifier 28′ and bypasses the actual humidification deviceor element, for example, in the form of a humidification pad. In orderto illustrate the bypass 30 and the fact that is arranged within thehumidifier 28′ it is shown with dashed lines. The arrows in FIG. 2illustrate the direction of the air flows in this embodiment.

The embodiment illustrated in FIG. 2 shows the air supply duct 2′connected to the two-way manifold 4′, which then separates the supplyair stream into a first air stream in the first duct 6′ and a second airstream in the second duct 10′. The first conduit 8′ and the secondconduit 12′ is also well illustrated and again the sequence on the firstduct 6′ of the first conduit inlet 20′ on the first duct 6, the secondconduit outlet 36′ on the first duct 6′, arranged upstream from thefirst conduit inlet 20′ is clearly visible. Also, the sequence on thesecond duct 10′ of the first conduit outlet 22′ being arrangeddownstream of the humidifier 28′ and the second conduit inlet 34′ beingarranged downstream of the first conduit outlet 22′ is also clearlyvisible as illustrated. These sequences are of importance to guaranteethe functioning of the humidification system 1, 1′.

FIG. 2 further illustrates a baffle element 50 arranged upstream of thefirst conduit inlet 20′ within the first duct 6′ and a baffle element 50arranged upstream of the second conduit inlet 34′ in the second duct10′. The baffle elements 50 may be perforated plates or the like orother guiding elements that create turbulence in the air stream for anoptimal mixing of the air stream once the dry and over humidified airstreams have been combined.

In addition, FIG. 2 illustrates a controlling element 16′ in the form ofa passive restrictor arranged in the first duct 6′ and the bypass 30′.The passive restrictor 16′ comprises a flat element, for example a discwith a hole in it, for example in the center, in which the disc isarranged within the first duct 6′ and/or the bypass 30′. As previouslymentioned, the passive restrictor(s) may be placed at any suitableposition within the humidification system 1′, 1 as well as in theembodiment shown in FIG. 1 . One or several or no restrictor may bearranged in the first and/or second duct 6, 6′, 10, 10′ and/or the firstconduit 8, 8′ and/or the second conduit 12, 12′. The amount andplacement of the restrictors depends on system requirements and design.

The embodiments of FIGS. 1 and 2 are interchangeable, this means thatany feature shown in FIG. 2 can be employed in the embodiment of FIG. 1and vice versa. In particular, the baffle elements 50 may also beinstalled in the embodiment of FIG. 1 and the controlling elements 16and pressure sensors 18 illustrated in the embodiment of FIG. 1 may befully or partially employed in the embodiment of FIG. 2 . As previouslystated, the controlling elements 16, 16′ may be embodied as fans, valvesor passive/active restrictors.

In any of the shown embodiments of FIGS. 1 and 2 , the first conduit 8,8′ and the second conduit 12, 12′ may be combined in one air pipe or thelike as long as the sequences of the first conduit inlet 20, 20′ andsecond conduit outlet 36, 36′ and first conduit outlet 22, 22′ andsecond conduit inlet 34, 34′ are respected.

Even though the embodiment of FIGS. 1 and 2 are both shown comprisingthe two-way manifold 4, 4′ and the air supply duct 2, 2′, this two-waymanifold 4, 4′ and air supply duct 2, 2′ may not be present and theinvention will still work or can still be employed. It could, forinstance, be possible that the first and second ducts 6, 6′, 10, 10′each comprise supply air streams taken from two different ports orpackers of the aircraft. In that case, the two-way manifold 4, 4′ is notpresent and the first duct 6, 6′ may comprise a supply air stream priorto reaching the humidifier 28, 28′ or bypass 30, 30′ and similarly,prior to reaching the second conduit outlet 36, 36′ the first duct 6, 6′may comprise a supply air stream.

The invention claimed is:
 1. A humidification system for aircraftscomprising: a first duct configured to guide a first air stream; asecond duct configured to guide a second air stream, said second ductcomprising a humidifier for humidifying the air in the second duct; afirst conduit for directing a part of the second air stream to the firstduct, said first conduit comprising a first conduit inlet leading intothe first duct and a first conduit outlet extending from the secondduct; and a second conduit for directing a part of the first air streamto the second duct, said second conduit comprising a second conduitinlet leading into the second duct and a second conduit outlet extendingfrom the first duct, wherein the first conduit outlet is arrangeddownstream of the humidifier, the second conduit inlet is arrangeddownstream of the first conduit outlet and wherein the first conduitinlet is arranged downstream of the second conduit outlet, and in whicheach of the first conduit, the second conduit, the first duct and thesecond duct are separate from one another, and wherein the first ductand the second duct each carry humidified air downstream the firstconduit inlet and downstream the second conduit inlet, respectively,when the humidification system is in use.
 2. The humidification systemaccording to claim 1, further comprising an air supply duct configuredto guide a supply air stream and a two-way manifold connected to the airsupply duct, the first duct and the second duct, whereby the air isconfigured to flow from the air supply duct into the two-way manifoldand then partially into the first duct and the second duct forming thefirst air stream and the second air stream.
 3. The humidification systemaccording to claim 1, wherein the humidifier is an adiabatic humidifier.4. The humidification system according to claim 1, further comprising abypass configured to bypass the humidifier on the second duct.
 5. Thehumidification system according to claim 4, wherein the bypass comprisesa controlling element.
 6. The humidification system according to claim1, wherein the first conduit and the second conduit are arranged in oneduct or pipe.
 7. The humidification system according to claim 1, whereinthe humidifier comprises a humidifying pad for humidifying the secondair stream.
 8. The humidification system according to claim 1, whereinthe first air stream and the second air stream comprise humidified airdownstream of the first conduit inlet and the second conduit inlet,respectively.
 9. The humidification system according to claim 1, whereinat least one of the first conduit or the second conduit comprises acontrolling element.
 10. The humidification system according to claim 1,wherein at least one of the first duct or the second duct comprises acontrolling element.
 11. The humidification system according to claim 1,wherein the first duct and the second duct comprise baffle elementsdownstream of the first conduit inlet and the second conduit inlet,respectively.
 12. The humidification system according to claim 10,wherein the first duct and/or the second duct comprises at least onepressure sensor.
 13. The humidification system according to claim 9,wherein the first conduit and/or the second conduit comprises at leastone pressure sensor.
 14. The humidification system according to claim 5,wherein the controlling element is at least one of a fan, a valve or arestrictor.
 15. The humidification system according to claim 12, whereinthe controlling element(s) and/or the pressure sensor(s) are connectedto a control unit configured to control an environmental control systemof the aircraft.
 16. The humidification system according to claim 9,wherein the controlling element(s) can be any of a fan, a valve or arestrictor.
 17. The humidification system of claim 10, wherein thecontrolling element can be any of a fan, a valve or a restrictor. 18.The humidification system of claim 13, wherein the controlling elementsand/or the pressure sensor(s) are connected to a control unit configuredto control an environmental control system of the aircraft.